1. Field of the Invention
The present invention relates to trap primers for supplying a small amount of water periodically to a drain trap.
2. Description of the Prior Art
When a drain is infrequently used, the water in its trap evaporates allowing sewer gas to enter the building. It is, therefore, necessary to provide an automatic device for supplying water periodically to the drain trap to keep it filled. Various types of prior art primer valves have been developed and used for that purpose.
In many instances the operation of drain trap primers may affect the flow of water through the waterline and not yield instantaneous flow to the water controlling device such as faucets. In other instances the drain trap primer may not properly control water to the trap and supply an excess amount of water thereto, and waste water.
Therefore, it is an object of the present invention to provide a drain trap primer to overcome these deficiencies.
The present invention is a trap primer that includes a body defining an inlet port, an outlet port and a trap primer port in fluid communication with a shut off cavity. A piston assembly is received within the shut off cavity. The piston assembly includes a piston movable in a longitudinal direction within the sealing cavity and a seat defining a passageway with the trap primer port. The seat is in fluid communication with the trap primer port. The piston is biased in a first position to block the passageway when liquid is not flowing through the body. The piston is adapted to move to a second position when fluid is flowing from the inlet port to the outlet port through the body, permitting fluid to flow through the passageway defined in the seat.
More specifically, the present invention is a trap primer that includes a body, a piston, and a seat. The body defines an inlet port, an outlet port, and a trap primer port in fluid communication with a shut off cavity. The piston assembly is received within the shut off cavity, the piston assembly includes a piston movable in a longitudinal direction within the shut off cavity. The seat defines a passageway in fluid communication with the trap primer port. The piston is biased in a first position to block the passageway of the seat when liquid is not flowing through the body. The piston is adapted to move to a second position when fluid is flowing from the inlet port to the outlet port through the body, permitting fluid to flow through the passageway of the seat.
The piston includes a piston sealing surface and a seat includes a seat sealing surface, wherein when the piston is in the first position, the seat sealing surface contacts the seat sealing surface and blocks the passageway, and when the piston is in the second position, the piston sealing surface is spaced a distance away from the seat sealing surface. Preferably, one of the seat sealing surfaces and the piston sealing surfaces is curved relative to the other of the seat sealing surface and the piston sealing surface. More preferably, the seat sealing surface is curved relative to the piston sealing surface.
The seat body is secured to the body of the trap primer. Preferably, the seat body is threadably secured to the body. The seat body can be generally cylindrical in shape and is solid with the exception of a passageway defined therein. Alternatively, the seat body is cylindrical shaped defining a hollow cavity, an inlet hole, and an outlet hole. The inlet hole, hollow cavity, and the outlet hole are in fluid communication with each other, and the inlet hole is in direct fluid communication with the shut off cavity and the outlet hole is in direct fluid communication with the trap primer port. The passageway is defined by the inlet hole, the hollow cavity, and the outlet hole. The inlet hole has an inlet hole diameter, the outlet hole has an outlet hole diameter, and the hollow cavity has a hollow cavity diameter, wherein the hollow cavity diameter is greater than the inlet hole diameter and outlet hole diameter. Preferably, the seat sealing surface defines the inlet hole and the seat sealing surface is frusta-spherical in shape.
The piston includes a piston body having a cylindrical portion with a tip extending therefrom. The tip defines the piston sealing surface. The tip includes a gasket seal that includes the piston sealing surface. Preferably, the gasket seal is made of rubber. Further, the piston includes a piston body having an outer surface, wherein the outer surface has a plurality of circumferentially-spaced fingers extending along the longitudinal direction. The fingers define finger passageways therebetween that extend in the longitudinal direction. The piston body also includes a open top portion that defines an internal cavity having an upper edge offset from upper portions of the finger, wherein spaces are defined between the fingers that are in fluid communication with the internal cavity and the finger passageways.
A biasing member, such as a spring, is received within the internal cavity and sandwiched between the body and the piston.
The present invention is also a method for changing a trap primer seat that includes providing a trap primer as described hereinabove removing a first trap primer seat, and replacing the first trap primer seat with a second trap primer seat. The method further includes providing that the second trap primer seat has at least one diameter of the inlet hole and the outlet hole being different than respective the diameters of the inlet hole and the outlet hole of the first trap primer seat.